The present invention relates to a flow control assembly, and more particularly to such an assembly including a valve for controlling the flow of a hot material.
There are many applications in which it is necessary to control the flow of extremely hot materials. One example of such an application is in the control of gases emanating from a coal gasification plant. In such a plant the exhaust gases are usually at a temperature of about 2000 degrees F. and usually contain ash, which is very abrasive.
A type of valve assembly often used to control fluids in applications of this type is the conventional ball valve in which a spherical rotor, having a lateral channel therethrough, is rotated either to expose or close the channel to fluid flow. However, conventional valves often do not function properly under such extremely high temperatures. The excessive heat destroys conventional rubber O-ring seals and causes thermal distortion, resulting in poor sealing characteristics. In addition the heat appreciably degrades the strength of the seal comprising the valve, leading to erosion by abrasive materials such as ash.